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| Home > Publications database > Comparison of the Code-Systems EB2-EIRENE and SAFE-EIRENE |
| Home > Publications database > Comparison of the Code-Systems EB2-EIRENE and SAFE-EIRENE |
| Book/Report | FZJ-2019-01427 |
1996
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/21634
Report No.: Juel-3220
Abstract: A decisive quest ion in plasma physics for nuclear fusion is how to extract from a TOKAMAK device the large amounts of energy and alpha particles produced in thecore plasma? Since these fluxes are mainly controlled by the plasma edge several magnetic configurations and geometrical features are proposed for this region. Until now in all concepts a system with a plasma-surface interface (target) is used to control the fluxes of particles and energy. The system has to be designed and optimizedto meet different requirements: • It should handle the intense, hot plasma exhaust, while the power density on the targets must stay below technologicallimits. • The interference with the high temperature core plasma should be not too strong to sustain the fusion reactions. • The system has to guarantee a sufficiently good particle exhaust, to remove the $\alpha$-particles out of the core. - In general, current experiments cannot be scaled to future devices, due to the lack of appropriate similarity parameters. Therefore model calculations of the plasma edge are necessary to optimize core conditions and to control heat and particle exhaust. In addition to that changes in the models may help to understand the behaviour of the plasma edge. First theoretical considerations started with simple 1-dimensional calculations, eithermodelling the radial transport or the transport along field lines. But in most experiments the fluxes in radial direction and parallel to the field are strongly coupled.Beginning with nearly pure diffusion across magnetic surfaces inside the separatrix the direction of the flow changes and in the region, where field lines intersect a material boundary ($\textbf{S}$crape $\textbf{O}$ff $\textbf{L}$ayer) the flow along field lines becomes comparable to the diffusion. This spatially localized contact with the targets combined with the strong gradients in plasma density and temperature ($\vert \vert$ $\vec{B}$ $\underline{and}$ $\bot$ $\vec{B}$) makes it unavoidable to use at least two-dimesional models. Moreover the various and complex interactions of the plasma with neutral particles or impurities generated at the targets has to be taken into account. One rapidly reaches a level of complication and of strong and nonlinear mutual dependence of the variables that a solution of the transport equations is only [...]
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